Simulation and performance analysis of a grid connected multilevel inverter considering either battery or solar PV as DC input sources

This paper proposes and analyzes the performance of a grid connected multilevel inverter topology with step up transformer for battery and Solar PV (SPV) as a dc source. The simulation is done in SIMULINK/ MATLAB Software. The RMS inverter output voltage at transformer's secondary side is kept slightly higher than the RMS grid voltage and the power transfer to the grid is controlled by controlling the phase lag angle of grid with respect to the inverter. It is shown that when the phase lag angle of the grid is changed, the THD in grid current, RMS grid current, active power and reactive power changes while RMS voltage at transformer primary & secondary and output voltage THD remains approximately the same. The simulation is done for battery as well as Solar PV and found that the results are approximately same. This paper shows that if the phases lag angle increases, the grid current THD reduces and RMS grid current increases. The simulation results with the variation of phase angle are tabulated and the variations of THD, P and Q with phase angle are shown graphically. These results are compared with those obtained from mathematical analysis and found to be in agreement.